An Internet Protocol (IP) Multimedia Subsystem (IMS) communication network may offer the possibility of using IP based functionalities for transferring voice data. In particular, an IMS communication network offers the functionalities of an execution of an IMS voice session and/or an execution of an IMS emergency voice session, which functionalities can be used by a terminal.
However, depending on the underlying network architecture of the IMS based communication network, it may happen that the IMS based communication network may only support an IMS voice session via a packet switched capable radio access network, but does not support an emergency session related data transmission via the packet switched capable radio access network. On the other hand, a terminal attached to the IMS based communication network may support both an IMS voice session and an IMS emergency session via the packet switched capable radio access network. Owing to regulatory requirements defined for an operator of the IMS communication network, the terminal is only allowed to use an IMS voice session for communication, if the IMS based communication network also supports the emergency session related data transmission via the packet switched capable radio access network. This scenario may apply, for example, for a terminal in accordance with Release 9 and an Evolved Packet Core (EPC) in accordance with Release 9 in combination with an IMS based communication network in accordance with Release 9.
Therefore an optimum usage of capabilities of the terminal is potentially not possible.